Association between SNP12 in estrogen receptor α gene and hypospadias: a systematic review and meta-analysis

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Table 1 Characteristic of the included studies

First author	Year	Setting	Ethnicity	Sample size (T/C)	Age (years) (T/C)	Design	Genotyping assay	Score	HWE
First author	Year	Setting	Ethnicity	Sample size (T/C)	Age (years) (T/C)	Design	Genotyping assay	Score	χ ²	P
L. F. van der Zanden	2010	Dutch	Caucasian	617/596	NA	Case–control	TaqMan	6	0.000	0.982
M. Watanabe	2007	Japan	Japanese	43/135	0–27/4–16 and 24–50	Case–control	PCR	8	1.520	0.218
K. F. Tang	2011	China	Chinese	72/40	2–19/1–15	Case–control	PCR	7	0.500	0.480
S. Choudhry	2015	USA	Hispanic and White	647/877	NA	Case–control	NA	8	NA	NA

NA not available, HWE Hardy–Weinberg equilibrium, PCR polymerase chain reaction, T case group, C control group